Adjustable stair assembly

ABSTRACT

An adjustable stair assembly in which the stair treads are adjustably supported on stringers so that the exposed tread surface may be selectively determined in proportion to the riser dimension from tread to tread, and the stringers are telescoped into upper and lower supports which anchor the assembly in the desired final position. In the assembly the stringers are used in pairs at each end of the treads and in conjunction with the upper and lower telescoping supports are selectively spaced to obtain the desired riser dimension and exposed tread width within acceptable standards of riser to tread dimensional ratios.

United States Patent 1 1 Hinkle 1 1 Jan. 30, 1973 541 ADJUSTABLE STAIRASSEMBLY 1,419,834 6/1922 Fellow ..182/1 [7 Inventor: Lioyd A. inkle,2l6 Piedmont 3,367,444 2/1968 Meddlck ..182/1 Avenue Pledmom 63957Primary ExaminerReinaldo P. Machado [22] Filed: June 14, 1971Att0rneyGravely, Lieder & Woodruff [21] Appl. No.: 152,791 [57] ABSTRACTAn adjustable stair assembly in which the stair treads [52] US. Cl...182/95, 182/1, 182/204, are adj-stably Supported on stringers so thatthe 52/]82 posed tread surface may be selectively determined in ll]!-Cl. p p i to the riser dimension f tread to tread [58] held of Search 3and the stringers are telescoped into upper and lower 52/182 183supports which anchor the assembly in the desired final position 1n theassembly the stringers are used in [56] References C'ted pairs at eachend of the treads and in conjunction with UNITED STATES PATENTS theupper and lower telescoping supports are selectlvely spaced to obtainthe desired riser dimension and 3,092,383 6/1963 Dunn ..182/115 exposedtread width within acceptable standards of 3,593,821 7/1971 Lister..182/115 riser to tread dimensional ratios, 3,150,742 9/1964 Carter..182/93 2,867,855 1/1959 Xanten ..182/93 7 Claims, 7 Drawing FiguresPATENTED JAN 30 I973 SHEET 8 BF 2 ADJUSTABLE sTArR- ASSEMBLY BRIEFDESCRIPTION OF THE INVENTION This invention relates to adjustable stairassemblies and is particularly concerned with the provision of staircomponents which will afford a range of stair angles in one assembly toaccommodate several arrangements from low to high angle stairs.

It has been a continuing problem in the erection of stairs that for agiven pitch of the stairs all of the components, such as stringers,treads and stringers attachments, need to be cut on the job site tomatch the rise between different levels. Notching of the stringers tosupport the treads is often difficult and tends to result in treads notall being level. The time needed to notch the stringers properly iscostly and skill is required to accomplish the work correctly.

Attempts have been made in the past to provide prefabricated stairassemblies, but such attempts have. not resulted in entirely solving themany problems which are found in actual practice due to wide variancesin the floor to floor spacing and the pitch preferences found best fordifferent people.

Accordingly the adjustable stairs of this disclosure embodies the uniquefeature of providing the stair stringers with slip members at both endsso that the stringers which carry the treads may be moved to a desiredpitch angle with a concomitant adjustment in the effective length of thestringers, whereby the pitch angle of the stringers is given a rangewithin the best ratio of tread width to riser heighth.

The presently preferred stair assembly solves the many problems byarranging the several components of the stair so that job siteadjustments may be made quickly and positively. In a presently preferredembodiment, the bottom and top supports for the stringers are made totelescope in the stringers so that the final pitch of the stair may beselected to suit the needs of those who use the stairs.

While stairs are most often required for use in permanent buildings,homes and like structures, there exists a need for stairs in connectionwith portable homes, and trailers to make access safer and moreconvenient. Therefore, another preferred embodiment of the presentadjustable stair combines the stair assembly with a cooperating upperlanding or porch, the new combination being detachable and foldable whenit is desired to move the trailer or portable home.

These and other features of the adjustable stair of this invention willbe more particularly set forth inv the drawings and accompanyingdescription.

DESCRIPTION OF THE DRAWINGS Several preferred embodiments of the presentadjustable stair will be disclosed in the drawings, wherein:

FIG. 1 is a side elevational view of an adjustable stair assemblyproviding access between an upper and lower level in a building;

FIG. 2 is a front elevational view of the stair assembly seen in FIG. 1;

FIG. 3 is a typical fragmentary sectional view taken at line 3-3 in FIG.1;

FIG. 4 is another fragmentary sectional view of the stair assembly seenat line 4-4 in FIG. 1;

FIG. 5 is a typical fragmentary sectional view of the telescopingcomponents of the stair assembly seen at line 5-5 in FIG. 1;

FIG. 6 is a side elevational view of a modified stair assembly showingthe combination of stairs and porchtype upper landing, and in which viewthe folding characteristics of the assembly has been indicated in brokenoutline; and

FIG. 7 is a somewhat schematic view in side elevation of the combinationof a plurality of the stair assembly ofFIG. 6.

DESCRIPTION OF THE STAIR ASSEMBLY In the view of FIGS. 1 and 2, theadjustable stair assembly herein preferred comprises tubular stringers10 being longer than the lower stringers 11 in order to accommodate thepitch of the stairs between the elevated level 12' and the lower level13. Each pair of stringers supports tread brackets 14 formed fromangular members. The vertical legs of the brackets 14 are connected bysuitable bolts 15 (FIGS. 3 and 4) to the adjacent stringers 10 and- 11,while the horizontal legs of these brackets 14 provide surfaces for thesupport of the ends of treads 16. The bolts 15 attaching the rear endsof the several brackets 14 to the lower stringers engage in horizontallydirected slots 17 while the bolts 15 attaching the front ends'of theseveral brackets 14 to the longer upper stringers l0 engage in similarhorizontally directed slots 17. The provision of slots 17 allows foraccommodating the fore and aft location of the treads 16 for adjustmentsof the pitch angle of the stringers.

The stair assembly of FIG. 1 is uniquely adjustable for various pitchangles by means of telescoping or slip members received in the ends ofthe respective stringers. Thus, at the upper level 12, anchor plates 18(FIGS. 1 and 2) are secured to the vertical face of the structure oflevel 12, and these plates are aligned with the respective pairs ofstringers l0 and 11. Each plate 18 carries an upper bracket 19, and alower bracket 20 having a vertically elongated slot 21 therein. Theupper brackets 19 support slip members 22 which are pivotally secured bybolts 23 at the upper ends. The lower end of each slip member 22telescopes into the adjacent open end of stringer 10 (FIG. 5) asufficient distance to provide a strong union of the two cooperatingparts. The lower bracket 20 supports a slip member 24 which is pivotallymounted at its outer end by a bolt 25 riding in the elongated slot 21.The inner end of the slip member 24 telescopes into the open end of theadjacent stringer 11, and this inner end is provided with an elongatedslot 26 so as to pass the tread bracket bolt 15.

The bottom of the stair assembly is connected to the surface of level 13by shoes 27' formed with spaced upstanding legs 28 which receivetherebetween (FIG. 2) the ends of slip member 29 for stringer 10 andslip member 30 for stringer 11. Each slip member 29 ispivotally-supportedbetween the legs 28 of shoe 27 by a bolt 31, and abolt 32 pivotally connects the slip member 30 between legs 28'of thesame shoe 27. Each slip member 29 and 30 telescopes into the end of thecooperating stringers l0 and 11 respectively, and each is formed with anelongated. slot 33 so as to pass upwardly beyond the bracket bolts 15-as seen in FIG. 1.

The installation of the stair assembly of FIG. 1, which assembly may bemade at the factory and transported to the job site in such condition,is achieved by securing the upper plates 18 to the vertical face oflevel 12 such that the top treadi 16 is at the desired step-up distanceor rise from level 12. The stringers and 11 at each side of the treads16 may then be moved out to the desired pitch angle by slidablytelescoping the stringers 10 and 11 on the respective slip members 22and 24. During the installation all bolts are sufficiently loose toallow for the telescoping adjustments required. The bottom shoes 27 arenext fixed in place on the surface of level 13 by telescoping adjustmentof the respective slip members 29 and 30 in the bottom ends of stringers10 and 11. At this time, the bolts 23 and 25 at the level 12 aretightened, as are the bolts 31 and 32 at the level 13. Following thisbolt tightening operation, stringers 11 are adjusted longitudinally upor down on the slip members 24 and 30 to the desired setting and setscrew 34 at slip members 30 are set in place to retain the stringers 11.Next stringers 10 are longitudinally positioned on the slip members 22and 29, and set screw 35 is set in place. The final adjustment of theposition of treads 16 is carried out along the direction of slots 17 andthe several bolts are tightened. After this operation all bolts aretightened to secure the components in the final positions.

In FIG. 6 parts and components similar to those described in FIG. 1 willbe designated by similar reference numerals. The assembly of this viewincludes stringers 10 and 11 which support the angle brackets 14 for thetreads 16. The lower ends of the stringers 10 and 11 are supported byshoes 27 having upstanding spaced legs 28. A slip member 36 is pivotallyconnected between legs 28, and its end is telescoped into the open endof stringer l0 and secured by a set screw 35. Similarly the stringer 11is connected by a slip member 37 telescoped therein, and the end ispivotally connected between the legs 28 of shoe 27. The stringer 11 issecured by set screw 34. The slip members 36 and 37 are provided withbolts 31 and 32 respectively which constitute the pivots at the shoe 27.

The upper end of stringer 10 is supported by a slip member 38 telescopedtherein. The outer end of the slip member 38 is pivotally bolted by bolt39 to a joist 40 which is one of several joists for carrying' the deck41 of the upper landing or porch. Likewise, the upper end of stringer 11is supported by slip member 42 telescoped therein, and the upper end ispivotally connected by bolt 43 to a porch joist 40.

Theporch or upper landing deck 41 is suitably supported on a pluralityoflegs 44 connected by bolts 45 to the joist 40. When the porch legs 44are properly set and the bolts 45 tightened, the stair assembly isadjusted to the desired pitch angle by sliding the stringers 10 and Honthe slip members to the desired rise between treads 16. After thisadjustment the shoes 23 are secured, and all bolts are tightened alongwith set screws 34 and 35. Of course, and as noted above, the treads 16are adjusted by moving each one in the direction of the horizontal slots17. It is understood that the elevation of the porch deck 41 will besuitable for the entrance to the mobile home or trailer (not shown).Porch supporting legs 44 are, of course, of a suitable length to meetthe requirements.

When the home or trailer is to be moved, the porch and stair assembly isreleased from its erected setting by loosening all bolts sufficiently toallow the deck 41 to be pivoted (as shown in broken line) in a clockwisedirection about the bolt 43 for slip member 42 of stringer 11 to itsfolded position. This folding action causes the stringer 10 and alltreads 16 to be folded inwardly until the stringer 10 lies adjacent thestringer 11.

FIG. 7 illustrates an organization of a plurality of stair assemblies,each one being similar to the assembly of FIG. 6. The difference is thatthe successively higher porch decks 41 require longer supporting legs44. In view of the similarities of the several components of thedisclosure in FIG. 7 to the detailed disclosure of FIG. 6 only the majorcomponents have been indicated by similar reference numerals to shortenthe description thereof.

In the various forms of the stair assembly shown it is to be understoodthat as the pitch angle is lowered or made less steep the pairs ofstringers are moved closer together and at the same time the exposedtread is'increased while the riser dimension is decreased. Conversely,when the pitch angle is increased or made steeper the exposed treaddecreases and the riser height increases. It is generally understoodthat the riser dimension for acceptable stairs may vary between 7 and 11inches, and the tread depth should be not less than about 10 inches. Thedimensions stated have been found to be suitable for the greatest numberof people, taking into account age, physical conditions, and eye sight.

When effecting an adjustment in the pitch angle, the slip members at thelower level shoes merely pivot, while the stringers may be slippedlongitudinally thereof to adjust the riser dimension of the first treadabove the lower level surface. On the opposite or upper ends of thestringers a compound adjustment must be made to take care of the changein spacing between stringers, as well as the proper longitudinallocation of the stringers on the slip members. In the several views ofthe accompanying drawings the adjustable stair has been shown with threetreads for simplicity. It is understood that the assembly may beconstructed with appropriate length stringers 10 and 11 to support anynumber of treads 16 deemed sufficient to provide access between an upperand a lower level.

What is claimed is:

1. An adjustable stair assembly to provide access between upper andlower levels comprising a pair of stringer members for each side of saidstair assembly, upper level support means for the upper ends of saidpairs of stringers, first means interconnecting said upper level supportmeans and the adjacent ends of each pair of said stringers, lower levelsupport means for the lower ends of said pairs of stringers, secondmeans interconnecting said lower level support means and the adjacentends of said pair of said stringers, said pairs of stringers beingadjustable relative to each other in each pair and to at least one ofsaid first and second means to accommodate a desired pitch angle forsaid stair assembly, said at least one of said first and second meansincluding bolt means, said bolt means on being tightened holding saidstringers at the desired pitch angle, and stair treads spanning saidpair of stringers.

2. The stair assembly of claim 1 wherein said stringers are tubularmembers, and said second means telescopically fit into the adjacent endsof said tubular stringer members for sliding adjustment to said desiredpitch angle for the assembly.

3. The stair assembly of claim 2 wherein set screws secure said tubularmembers to said second means whereby the tubular members are securedagainst longitudinal displacement.

4. The stair assembly of claim 1 wherein the upper level support meansis a porch deck extending horizontally from said first members, and legmeans engaged and support said porch deck in horizontal set position.

5. The stair assembly of claim 4 wherein said first and second meansslidingly engage the respective adjacent ends of said stringer membersand said first means pivotally engage said deck, whereby said deck isfoldable about one of said stringer members at eachside and causes theremaining one of said stringer member to fold into adjacency with saidone stringer member, whereby said stair assembly is foldable intocollapsed position.

6. An adjustable stair assembly between upper and lower levelscomprising two pairs of stringer members, one pair at each side of thestair assembly, first support means slidably engaged with the upper endsof said pairs of stringer members and pivotally connected to the upperlevel, second support means slidably engaged with the lower ends of saidpairs of stringer members and pivotally connected to the lower level,bracket means pivotally connected to and spanning the stringer membersof each pair thereof, treads supported on said bracket means andextending generally horizontally between said pairs of stringer membersto form the supporting stair surfaces, bolt means constituting thepivotal connections for tightening to retain the stair as sembly inposition.

7. The stair assembly of claim 6 wherein said stringer members aretubular and said first and second support means telescopingly slide insaid stringer members, whereby said stair assembly is renderedadjustable to a selected pitch angle for adjusting the rise between saidtreads.

1. An adjustable stair assembly to provide access between upper andlower levels comprising a pair of stringer members for each side of saidstair assembly, upper level support means for the upper ends of saidpairs of stringers, first means interconnecting said upper level supportmeans and the adjacent ends of each pair of said stringers, lower levelsupport means for the lower ends of said pairs of stringers, secondmeans interconnecting said lower level support means and the adjacentends of said pair of said stringers, said pairs of stringers beingadjustable relative to each other in each pair and to at least one ofsaid first and second means to accommodate a desired pitch angle forsaid stair assembly, said at least one of said first and second meansincluding bolt means, said bolt means on being tightened holding saidstringers at the desired pitch angle, and stair treads spanning saidpair of stringers.
 1. An adjustable stair assembly to provide accessbetween upper and lower levels comprising a pair of stringer members foreach side of said stair assembly, upper level support means for theupper ends of said pairs of stringers, first means interconnecting saidupper level support means and the adjacent ends of each pair of saidstringers, lower level support means for the lower ends of said pairs ofstringers, second means interconnecting said lower level support meansand the adjacent ends of said pair of said stringers, said pairs ofstringers being adjustable relative to each other in each pair and to atleast one of said first and second means to accommodate a desired pitchangle for said stair assembly, said at least one of said first andsecond means including bolt means, said bolt means on being tightenedholding said stringers at the desired pitch angle, and stair treadsspanning said pair of stringers.
 2. The stair assembly of claim 1wherein said stringers are tubular members, and said second meanstelescopically fit into the adjacent ends of said tubular stringermembers for sliding adjustment to said desired pitch angle for theassembly.
 3. The stair assembly of claim 2 wherein set screws securesaid tubular members to said second means whereby the tubular membersare secured against longitudinal displacement.
 4. The stair assembly ofclaim 1 wherein the upper level support means is a porch deck extendinghorizontally from said first members, and leg means engaged and supportsaid porch deck in horizontal set position.
 5. The stair assembly ofclaim 4 wherein said first and second means slidingly engage therespective adjacent ends of said stringer members and said first meanspivotally engage said deck, whereby said deck is foldable about one ofsaid stringer members at each side and causes the remaining one of saidstringer member to fold into adjacency with said one stringer member,whereby said stair assembly is foldable into collapsed position.
 6. Anadjustable stair assembly between upper and lower levels comprising twopairs of stringer members, one pair at each side of the stair assembly,first support means slidably engaged with the upper ends of said pairsof stringer members and pivotally connected to the upper level, secondsupport means slidably engaged with the lower ends of said pairs ofstringer members and pivotally connected to the lower level, bracketmeans pivotally connected to and spanning the stringer members of eachpair thereof, treads supported on said bracket means and extendinggenerally horizontally between said pairs of stringer members to formthe supporting stair surfaces, bolt means constituting the pivotalconnections for tightening to retain the stair assembly in position.